﻿<!DOCTYPE html>
<html>
<head>
<!--
  Copyright (c) 2017-2018 Jean-Marc VIGLINO, 
  released under CeCILL-B (french BSD like) licence: http://www.cecill.info/
-->
  <title>ol-ext: Graticule control</title>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

  <link rel="stylesheet" href="../style.css" />

  <!-- jQuery -->
  <script type="text/javascript" src="https://code.jquery.com/jquery-1.11.0.min.js"></script>

  <!-- Openlayers -->
  <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/ol@latest/ol.css" />
  <script type="text/javascript" src="https://cdn.jsdelivr.net/npm/ol@latest/dist/ol.js"></script>
  <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL,Object.assign"></script>
  
  <!-- ol-ext -->
  <link rel="stylesheet" href="../../dist/ol-ext.css" />
  <script type="text/javascript" src="../../dist/ol-ext.js"></script>
  <!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
  <script src="https://unpkg.com/elm-pep"></script>
  
  <!-- Proj4 -->
  <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.3.14/proj4.js"></script>
  
  <style>
    #map {
      background: #fff;
      border:1px solid #000;
      padding:1em;
      width: 100%;
      height: calc(100vh - 10em);
      box-sizing: border-box;
    }
    .ol-mouse-position {
      top: auto;
      bottom: 1em;
      left: 50%;
      right:auto;
      position: absolute;
      transform: translateX(-50%);
      background: rgba(255,255,255,0.5);
      font-size: 14px;
    }
  </style>
</head>
<body >
  <a href="https://github.com/Viglino/ol-ext" class="icss-github-corner"><i></i></a>

  <a href="../../index.html">
    <h1>ol-ext: Graticule control</h1>
  </a>
  <div class="info">
    This example use <i>ol.control.Graticule</i> show a MGRS graticule on the map (use precision and intervals options) -
    <a href="https://codesandbox.io/s/mgrs-forked-q6q17i?file=/main.js">original idea Mike-000</a>
  </div>

  <!-- Map div -->
  <div id="map"></div>

  <script type="text/javascript">
// Define UTM zones
var utmProjs = [];
for (let zone = 1; zone <= 60; zone++) {
  var code = 'EPSG:' + (32600 + zone);
  proj4.defs(
    code,
    '+proj=utm +zone=' + zone + ' +ellps=WGS84 +datum=WGS84 +units=m +no_defs'
  );
  ol.proj.proj4.register(proj4);
  utmProjs[zone] = ol.proj.get(code);
}

var llProj = ol.proj.get('EPSG:4326');

var midpointX = 500000;
var width = midpointX * 2;

// Convert UTM coords from lonlat
function ll2utm(ll) {
  var world = Math.floor((ll[0] + 180) / 360);
  var lon = (((ll[0] % 360) + 540) % 360) - 180; // normalise any wrapx
  var lat = ll[1];
  var zone = Math.floor((180 + lon) / 6) + 1;
  var zoneCoord = ol.proj.transform([lon, lat], llProj, utmProjs[zone]);
  var coord = [zoneCoord[0] + (zone - 1) * width, zoneCoord[1]];
  coord[0] += world * 60 * width;
  return coord;
}

// Convert UTM coords to lonlat
function utm2ll(coord) {
  var world = Math.floor(coord[0] / (60 * width));
  var zone = (Math.floor(coord[0] / width) % 60) + 1;
  var c0 = coord[0] % width;
  var c1 = coord[1];
  var ll = ol.proj.transform([c0, c1], utmProjs[zone], llProj);
  if (Math.floor((180 + ll[0]) / 6) + 1 != zone) {
    ll[0] = (zone - (c0 < midpointX ? 1 : 0)) * 6 - 180;
  }
  ll[0] += world * 360;
  return ll;
}

// Define MGRS (UTM) projection / transform
const mgrs = new ol.proj.Projection({
  code: 'MGRS',
  units: 'm',
  extent: [0, -10000000, 60 * width, 10000000],
  global: true,
});
ol.proj.addProjection(mgrs);
ol.proj.addCoordinateTransforms(llProj, mgrs, ll2utm, utm2ll);

// Create map
const map = new ol.Map({
  layers: [
    new ol.layer.Tile({
      source: new ol.source.OSM(),
    }),
  ],
  target: 'map',
  // controls: ol.control.defaults({attribution: false}),
  view: new ol.View({
    center: [259289, 5872518],
    zoom: 6,
  }),
});

// Add transform
const viewProj = map.getView().getProjection();
ol.proj.addCoordinateTransforms(
  viewProj,
  mgrs,
  function (coord) {
    return ll2utm(ol.proj.transform(coord, viewProj, llProj));
  },
  function (coord) {
    return ol.proj.transform(utm2ll(coord), llProj, viewProj);
  }
);

// Create Graticule with intervals / precisions
map.addControl(
  new ol.control.Graticule({
    projection: 'MGRS',
    step: 1000,
    stepCoord: 1,
    intervals: [
      1000000,
      500000,
      200000,
      100000,
      50000,
      20000,
      10000,
      5000,
      2000,
      1000,
    ],
    precision: 50000,
    formatCoord: function (coord, position) {
      if (position === 'left' || position === 'right') {
        const y = coord + 10000000;
        const index = Math.floor(y / 1000000);
        const code = 'CDEFGHJKLMNPQRSTUVWX'.charAt(index);
        const kmy = (1000 + (Math.floor(y / 1000) % 1000)).toString().slice(1);
        return code + (kmy === '000' ? '' : ' ' + kmy);
      } else {
        const zone = (100 + (Math.floor(coord / width) % 60) + 1)
          .toString()
          .slice(1);
        const kmx = (1000 + (Math.floor(coord / 1000) % 1000))
          .toString()
          .slice(1);
        return zone + (kmx === '000' ? '' : ' ' + kmx);
      }
    },
  })
);
  </script>

</body>
</html>